Earth's Interior

Earth's Interior
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Earth's interior
Planets are structured into distinct layers. The layers appear in the order of densities of the materials making up these layers. The densest materials form the innermost layers while the least dense form the outermost layer. For planet earth, these layers from the innermost to the outermost are the iron core, mantle, crust, Liquid Ocean and the atmosphere. Understanding the layered structure of the earth is not an easy thing and requires a lot of scientific techniques. Study of seismic waves produced by earthquakes, mineral physics experiments, and gravity measurements are some of the methods used to study the patterns of earth's deep motions. Nebular debris melt and segregates into layers and this is what forms the different layers of planets.Seismic waves
The property of the Earth's layers includes the physical state and composition of the materials making up each of the layers as well as how stiff these materials are. Density determines the layers of the earth, the heaviest materials forms the center of the earth and the lightest ones on the outside of the earth. Geophysical techniques and the study of seismic waves have shown the earth as comprising of interacting parts. Many earthquakes are large enough that their waves can be detected and measured on the earth's surface. What becomes more challenging is interpreting seismic waves recorded on seismographs as seismic waves do not travel on straight paths. The waves are reflected, refracted, and diffracted as they pass through the different layers of our planet. Changes in the structure of rocks makes seismic waves to be reflected off between different layers a characteristic that is especially important in the exploration for natural gas and oil. Mapping the layering of the upper crust helps identify petroleum which appears as being trapped in specific kind of geological structures. Seismic waves are also useful in identifying the boundaries between the crust, mantle, inner and outer core. Seismic waves travel faster in stiff or less compressible materials. Seismologists use this property to determine the composition and temperatures of different rocks. Seismic waves travel in refracted paths because their velocities increase with increase in depth. Velocities increase with depth because as pressure increases, it squeezes the rocks into more compact rigid materialsCITATION Ben04 \p 17 \l 1033 (Pluijm and al 17).
Earth's layers
Continental crust and oceanic crust forms the earth's crust. The two have very different compositions despite both forming up the crust. Oceanic crust forms at mid ocean ridges separating two diverging tectonic plates and averages about seven kilometers thick. Continental crust on the other hand is about 40 kilometers in thickness. In 1909, Croatian seismologist Andrija Mohorovicic discovered Moho, the boundery between the crust and mantle. He studied two waves travelling at different speed and discovered that they could only be travelling through different layers. The mantle consists of more than 82 percent of Earth's volume. ...